OTL38, a tumor-specific fluorescent compound that “lights up” ovarian tumor tissue during surgery, helped doctors to detect and remove cancer cells that would otherwise be missed, final results of a Phase 2 study show. The study, “A phase II, multicenter, open-label trial of OTL38 injection for the intra-operative imaging of folate receptor-alpha positive ovarian cancer,” was published in the journal Gynecologic Oncology. "OTL38 can intraoperatively identify more ovarian cancer lesions during ... surgery than traditional detection techniques alone which enables a better outcome for patients," Chris Barys, CEO of On Target Laboratories, which developed OTL38, said in a news release. The positive data has led to a Phase 3 study (NCT03180307) currently evaluating the safety and effectiveness of OTL38, compared with current methods, in detecting additional ovarian cancer cells during surgery. The complete removal of a tumor during surgery helps to avoid additional surgeries and cancer relapse, but, most importantly, to increase patients’ overall survival. Currently, the strongest predictor of overall survival is the removal of all macroscopic disease during surgery, where the doctor distinguishes cancer from healthy tissue by visual inspection and palpation. Fluorescence-guided surgery, which combines imaging techniques and tumor-specific fluorescent tracers — fluorescent compounds that selectively bind to tumors — has the potential to provide highly specific real-time detection of tumors during surgery, illuminating cancer cells that once evaded standard detection. OTL38, consisting of a folic acid molecule bound to a green-like near-infrared dye, is designed to bind to folate receptor alpha (FRa) in cancer cells and accumulate inside them.